1. Field of the Invention
The present invention generally relates to an apparatus for changing the attack of a cavitator on a supercavitating underwater research model.
2. Description of the Prior Art
Supercavitating underwater vehicles and projectiles are known in the art. One such supercavitating underwater projectile is described in Harkins et al., U.S. Pat. No. 5,955,698. This projectile uses a supercavitating nose section that provides a cavitation bubble of sufficient size to encompass the body of the projectile which reduces hydrodynamic drag. The cavitating nose section described in the Harkins et al. is a fixed position cavitating nose section and cannot be maneuvered so as to vary the angle of attack of the projectile. Brown et al., U.S. Pat. No. 5,929,370 discloses another underwater projectile having a fixed-position nose assembly.
The development of supercavitating underwater vehicles depends heavily upon supercavitating underwater research models. Typically, the supercavitating underwater research model is positioned in a large tow tank that is filled with water. In order to change the angle of attack of the supercavitating underwater research model, the tow tank must be drained so as to enable personnel to adjust some of the mechanical components on the nose assembly. However, this is a time consuming endeavor because a significant amount of time is needed to fill and drain the tow tank. What is needed is an apparatus that that can vary the angle of attack of the cavitator on a supercavitating underwater research model while the tow tank is filled with water and the supercavitating underwater research model is still in motion. The prior art discloses several moveable nose assemblies, however, such assemblies are not suitable for use with supercavitating underwater research models. For example, Patterson, U.S. Pat. No. 3,069,112 discloses a missile nose assembly that pivots about the missile's longitudinal axis. Thomson, U.S. Pat. No. 4,579,298 discloses a pivotable nose assembly having a plurality of pivoting actuators that are coupled to the nose's base. Kranz, U.S. Pat. No. 4,793,571 discloses a pivotable nose assembly having a plurality of actuating plungers coupled to an end plate of the nose. Moskovitz, U.S. patent No. discloses a rotatable nose assembly for an aircraft. Becker et al., U.S. Pat. No. 5,631,442 discloses a pivotable warhead assembly having a plurality of bellows that cooperate to cause a charge to pivot about a ball joint. None of these prior art patents disclose an apparatus that addresses the aforementioned problem of changing the angle of attack of a supercavitating underwater research model while such model is in motion and underwater.